Under current New York law, an accusation is first vetted by an independent investigator. (In New York City, that's the special commissioner of investigation; elsewhere in the state, it can be an independent law firm or the local school superintendent.) Then the case goes before an employment arbitrator. The local teachers union and school district together choose the arbitrators, who in turn are paid up to $1,400 per day. And therein lies the problem.

For many arbitrators, their livelihood depends on pleasing the unions (whether the United Federation of Teachers in New York City, or other local unions). And the unions -- believing that they are helping the cause of teachers by being weak on sexual predators -- prefer suspensions and fines, and not dismissal, for teachers charged with inappropriate sexual conduct.

During a radio appearance in April, Bloomberg quipped of the arbitrators’ rulings, “maybe if you were a serial ax murderer, you might get a slap on the wrist.” Like Brown, he noted that arbitrators might have been inclined to impose milder penalties in an effort to keep their jobs.

In May, the mayor proposed a new state law that gives high-ranking, local school officials the ultimate authority when deciding whether school employees implicated in sex cases should be terminated.

"There is simply no reason that teachers accused of sexual misconduct should have greater job security than other city employees," he said at the time. "The fact that they currently do is wrong; it is dangerous; it is indefensible."

In concluding his piece, Casey writes “The entirely false slander that we protect and defend sexual predators is, for us, the equivalent of a blood libel. There are not words to describe the feelings of anger and outrage we have that the Mayor of the City of New York and his proxies would stoop to such contemptible falsehoods.”

In an email to BuzzFeed, Abraham Foxman, president of the Anti-Defamation League, called Casey’s use of the phrase “blood libel” -- which the UFT vice president linked to in his post -- "inappropriate and over-the-top," adding that because the statement was made by a midlevel official of a local union, Foxman would not be paying it much attention.

I have a great deal of respect for Mr. Foxman and the ADL. I would simply say that while we are accustomed to having our positions misrepresented by the Mayor and his proxies, the slander that a union of teachers protects sexual predators and seeks to have them remain in the classroom was so beyond the pale of acceptable discourse, so utterly violative of our life’s work as educators and unionists, so cynical in its use of children in an attempt to demonize us with falsehood, that it evoked that comparison for me. I regret if it was in any way disturbing to Mr. Foxman.